This invention relates to a liquid crystal display unit and a method for manufacturing the same. More particularly, the present invention relates to a spacer structure for maintaining a gap formed between two substrates in a liquid crystal display unit and a method for manufacturing such a spacer structure.
As known, a typical liquid crystal display unit comprises two substrates and a liquid crystal filled in a small gap (for example, 2 to 3 .mu.m) formed therebetween, and its displaying function is exhibited by appropriately controlling the supply of voltage to the liquid crystal through plurality of electrodes which are arranged in a matrix pattern. In order to prevent displaying irregularity, it is necessary for such a liquid crystal display unit that the gap is formed uniformly so that the thickness of the liquid crystal to be filled in the gap will be uniform.
Conventionally, tiny spacers consisting of a large number of aluminum powders, glass beads and the like are sprayed to one of the two substrates, and the other substrate is placed on it such that tiny spacers are provided between the two substrates in a scattered arrangement, thereby uniformly maintaining a gap.
However, in the above-mentioned method, it is difficult to uniformly distribute the spacers on the substrate. Moreover, it is required to take a high level of an anti-dust countermeasure when the spacers are sprayed. Therefore, the cost is increased in the process for forming the gap.
In addition, in the construction in which a large number of spacers are provided between the two substrates in a scattered arrangement as mentioned above, the spacers tend to move when a liquid crystal is filled or due to long time use. Therefore, there is a possibility that the yield of production of the liquid crystal display units is decreased or the displaying function is degraded due to long time use.
In German Patent No. 2344050, a gap is formed between two substrates by a plurality of tiny projections formed on one of the two substrates and caused to contact the other substrate. However, since those tiny projections each have an annular configuration so that their sharp edges contact the other substrate, there is a possibility that the edges are broken.
European Patent No. 690028A1 discloses a method for forming tiny projections on a glass plate using a laser beam. However, since this method is developed for the use of forming micro lenses, it is irrelevant to the liquid crystal display unit.